Video captured by installed cameras is monitored to perform various determination. One such determination concerns whether or not the situation of a captured monitoring target is an event that needs to be observed.
For example, Patent Literature (PTL) 1 describes a method of detecting abnormal situations that occur on general roads or expressways, in parking areas, etc. In the method described in PTL 1 , a received acoustic signal is analyzed to determine whether or not to capture an image and, in the case of determining that an image needs to be captured, an imaging device is controlled so that its imaging range includes the device that has received the acoustic signal.